Discharge of the centrifugal substance from a centrifugal drum



c. SCHMITZ Marchs, 1940.

DISCH ARGE OF THE CENTRIFUGAL SUBSTANCE FROM A'CENTRIFUGAL DRUM OriginalFiled April 7, 1934 ill/III! v Patented Mar. 5, 1940 UNITED STATESPATENT OFFlCE DISCHARGE OF THE CENTRIFUGAL SUB- STANCE FROM"ACENTRIFUGAL DRUM Carl Schmitz, Oelde, Germany Original application April7, 1934, Serial-No.

719,543. Divided and this application Febru ary 7, 1935, Serial No. 5,47

'0ct0ber 25, 1933 1 Claim.

the lossesthe treatment of the milk in the next following apparatus isoften accompanied by difliculties.

- It is an object of the invention to provide improved means forpreventing the formation of froth in a machine ofthe kind referred to.

To this end, in combination-with a bowl or 16 drum arranged to rotateabout a vertical axis, a stationary tube is arranged with its axis inthe axis of rotation of the drum, a tubular stripper is connected to thetube at its upper end, a hollow driving spindle is connected to the drumat,

20 its upper end, a hollow driving spindle is connected to the centre ofthe bowl with its upper end and surrounds the stripper tube in co-axialrelation, and means are provided for producing back pressure in thestationary stripper tube. Without the back-pressure producing means, thestripper would remove so much of the surface layer on the inner side ofthe hollow paraboloid formed by the liquid under centrifugal action,that the ends of the stripper would be tangent to the side, and the airwould have free access. Under the back pressure, however, the liquid inthe stripper tube is backed up and the consequence is that a surfacelayer of liquid is presented to the stripper whose depth is such thataccess of air to the stripper is prevented, and so no froth can form.The hydraulic seal established by the back-pressure producing means ispreferable to mechanical packing means as heretofore provided, forobvious reasons.

An embodiment of the invention is illustrated by way of example in theaccompanying drawing in which Fig. 1 shows a centrifugal separator invertical section.

Fig. 2 is a horizontal section through the stripper.

A stationary tube 3 with a stripper 4 at its upper end is surrounded inco-axial relation by the hollow driving spindle of a centrifugal drum 5o2. The tube 3 and the spindle l-make .up an annular space 8. A bearingl5 for a journal at the upper end of the stripper tube 3 is formed in ahorizontal partition I6 arranged above, and

, ball bearings in the frame of the machine.

In Germany serted centrally in the bottom of the drum or bowl, and thespindle is supported by two radical The drum, or bowl, is a cylinderwitha tapered top, and I3 are cream holes at the upper end of the top. Thestripper 4 extends into a stripping chamber 6 separated from thecentrifuging chamber 5 by the partition l6. Arranged at the lower end ofthe hollow driving spindle l is a stuiling'box 9 or some other, forexample liquid seal for closing the lower end of the space 8. Ahorizontal discharge pipe II, with a cock l2, or other suitable meansfor varying its free sectional area, is connected to the lower end ofthe spindle l below the seal 9, and a pressure gauge I4 is connected tothe discharge pipe.

Vanes l whose inner ends extend into the vicinity of the strippers ends,arearranged in the chamberli between the partition l6 and the bottom ofthe drum or bowl 2, and ports! near the inner wall of the drum or bowl 2connect its interior to the chamber.

When the spindle l is rotated, the centrifuged liquid forms about thestripper 4 a hollow body of revolution. It will be understood that,since the liquid has free access to the chamber 6 through the ports Ithe hollow body is continuous, i. e., not interrupted by the partitionI6 I and the tapered side wallof the chamber 6. Owing to theconsiderable height of the body, the portion which is in the chamber 6may be considered practicallyas a hollow cylinder, the departure from aparaboloid being negligible. The ends of the stripper 4 enter into thecylinder and remove a certain percentage of the rotating liquid. If thisliquid were allowed to flow freely from the lower end of the stationarytube IS, a condition would soon be established in which the ends of thestripper 4 would be practically tangent to the hollow cylinder of liquidin the chamber 6. In order to prevent this, and to keep the ends of thestripper immersed in the body of liquid to a depth sufficient for thepermanent exclusion of air, back pressure is established in the tube 3by means of the cock I! in the discharge pipe I I, and the back pressureis indicated at the gauge l4. Only a short depth of penetration into thehollow liquid cylinder in the chamber 6 is necessary for a froth-freedelivery with low back pressure in the tube ll. inside diameter of thiscylinder is considerably smaller than the inside diameter of the drumand the diameter of the stripping circle is correspondingly small. Thisresults in a slightffrictional resistance at the outer ends of thestripper The 4 and enables the drum to rotate at the high speed which isnecessary for skimming and which could not be economically attained witha greater depth of penetration.

As compared with known separators the advantage is also derived that thecream discharge zone at I3 may be of small diameter so that the cream isdischarged at low speed.

The invention may also be employed for centrifuged substances which areonly to be cleansed. The admission and the discharge of the separatedportion of the liquid are efiected througli tightly closed connectionswith the drum. A plurality of devices according to the invention mayalso be employed in one drum.

As with the closed admission the pressure for forcing the centrifugedsubstance through the apparatus is lacking or considerably reduced, thepacking on the feed pipe is relieved.

I claim:

A machine for centrifuging liquids having a the liquid, a stationarytube arranged concen-' trically with the drum axis and communicatingwith said stripper, said tube serving for leading ofi the liquid fromsaid stripper, and a throttle element on said tube accessible from theouter side and adapted to influence the leading oii of the liquid andconsequently the liquid level in the stripper chamber for preserving aliquid seal between said stripper and said stripper chamber. CARLSCHMITZ.

